5 MB/sec and 10 MB/sec.

[MiniMe69]

I have a scsi-2 controller card that is capable of 5MB/sec transfer and 10MB/sec transfer...is that 5Megabytes or 5Megabits per second? Yes they use the capital MB. By the way what is the conversion to get 5 Megabytes to Megabits. is it x8 or /8 ? since 1 byte = 8 bits. would 5MB = 40 Mb?

 

[Noriaki]

Yes, 5MB = 40Mb

And SCSI is rated in MB not Mb.

 

[Doctorweir]

SCSI trsnsfer rates are given in MegaBYTE, so Fast SCSI (SCSI2) is 10 Megabyte or 80 MegaBit per secound...
Ultra 160 is 160 MegaByte...:Q...get yourself a load of this one...
I Only have Ultrawide (40 MB)

 

[MiniMe69]

so scsi-2 is better then the ata 33 and the ata 66 since those are rated in 33Mb and 66Mb per second? is this correct or no?

 

[Guilty]

Not really... SCSI's theoretical bandwidth is meant to be wide enough for multiple devices, no single drive is going to saturate 160MB/s. This is what confuses a lot of people into thinking SCSI is ridiulously "faster" than IDE. Since SCSI controllers can multitask, 4 drives can use the same Ultra160 channel at once. And since most drives, both SCSI and IDE, cant even or just barely break the 40MB/s barrier, thats enough for them to send at full potential simultaniously.

Secondly, ATA33 is rated at 33MB/s, B for bytes. ATA66 is 66MB/s.
So no, SCSI-2 is not "better" than either ATA standard.

 

[MiniMe69]

damn scsi-2 sucks...so slow...

 

[mrMaC]

SCSI-2 wasn't meant for performance I don't think tho, at least not over IDE
CPU usage was also a big thing in systems with older SCSI, and when doing something with your HD on IDE chain, bigtime CPU usage, but there's little/no CPU usage with SCSI, this is another reason SCSI is more expensive than IDE

 

[tristan]

the word "better" is relative.

but when we speak of disk performance,it should be noted that it is not only a function of the drive itself and certainly not by those theoretical figures alone. performance is also dependent on the controller, buffersize, and application,make and model of disk and implementation etc.

on a single disk PC, a scsi2 performance shouldn't be much different from an IDE ATA33/66, because of overhead, ATA33/66 sometimes is even faster and also becasue ATA66 is relatively new, manufacturing technology also comes into play.

But because scsi is targeted on server and high-end system, given the price range, a manufacturer can usually squeeze in more buffer, and more buffer generally means faster...so it is also a factor to look at.

it is on a RAID disk subsystem scsi really shines because of it's superior multitasking features....


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remind me how lucky I am to be MSCE - I keep forgeting...